In his first comments since Israeli troops laid siege Friday to Arafat's headquarters in the West Bank, the president urged all Middle East leaders to "do everything in their power" to stop the cycle of violence. He mentioned cutting off funds for terrorist groups and ensuring that members do not find safe haven.

But though he was speaking to all the region's leaders, and singled out Iran and Syria as needing to do more, Bush had especially harsh words for Arafat.

"I believe he can do a lot more to prevent attacks," Bush said at his Texas ranch where he had kept a silence while monitoring Friday's developments.

The president said Arafat should use both his bully pulpit — by speaking in Arabic directly to his people — and his security forces to stop the violence.

"He's got a lot of people that listen to him still," Bush said. "He's got to make it absolutely clear that the Palestinian Authority does not support these terrorist activities."

Bush said Israel's actions are understandable in the midst of "a wave of suicide bombers coming to the heart of their cities and killing innocent people."

"I fully understand Israel's need to defend herself. I respect that," Bush said.

But Bush urged Israel to work to reduce the violence as well, by making sure "that there is a path to peace as she secures her homeland."

The president said U.S. envoy Anthony Zinni will remain in the region to continue his efforts at arranging a cease-fire.

Just before Bush began speaking, there was fresh violence in Israeli. An explosion went off Saturday evening in a cafe in Tel Aviv's crowded entertainment district. Police and paramedics said the suicide bomber was killed and at least 24 guests were wounded.

Bush also stepped up Mideast diplomacy Saturday with calls to five world leaders. But he announced no new action by his administration to end the bloodshed, such as sending Vice President Dick Cheney back to the region.

Asked if he thought his administration could do more to help bring peace to the region, Bush said U.S. officials are spending "a great deal of time" on the matter and are committed to ending terrorism in the Middle East and around the world.

"Every phone call I make, I remind people that are interested in peace, and the leaders I've talked to are interested in peace, we've all got to come together to stop terror," Bush said. "I firmly believe that we can achieve a peace in the region, but not until there is a concerted, united effort to rout terror out."

Bush made calls from the ranch to King Abdullah II of Jordan, Egyptian President Hosni Mubarak, U.N. Secretary-General Kofi Annan, Prime Minister Jose Maria Aznar of Spain and Saudi Crown Prince Abdullah, who has offered a leading peace initiative.

The president did not speak with Arafat or Israeli Prime Minister Ariel Sharon.

White House spokesman Gordon Johndroe said the conversations covered the Middle East, but did not indicate what Bush heard from the leaders.

Spanish officials said Bush and Aznar, who holds the rotating chairmanship of the European Union, agreed on the need to find a common EU-U.S. position regarding a solution to the crisis.

Jordan's king urged Bush to intercede quickly so Israel would end its "aggression on the Palestinian people and the siege on President Arafat," the official Petra news agency said.

Abdullah said continued Israeli military escalation "warns of dangerous consequences in which things will get out of control and shake the stability and security of the whole region."

The president also had a conference call with Secretary of State Colin Powell and Condoleezza Rice, his national security adviser.